Has anyone used the baby king bottle straw or something similar?

Baby Bottle Straw - 2 Pack - Baby King Products

If you have and recommend it, where can I buy it? My baby is refusing to use a trainer cup at the moment. The ones I've seen are the Pigeon bottles. Since they are not BPA free, I don't want to buy one to try. I have Avent bottles and I wonder if it will work with it.

Any information would be greatly appreciated.